Organic vegetables are no healthier than those grown conventionally, according to a university study.

Agricultural scientists grew potatoes, carrots and onions under both organic and traditional conditions then tested the health-giving properties of each.

They found there was little difference in the amount of polyphenols, the chemical compound in vegetables that helps fight cancer, heart disease and dementia.

Little difference: Organic and ordinary produce was found to have similar levels of cancer-fighting chemicals

Organic crops are more expensive and are often perceived as being healthier, though consumers also cite environmental concerns, taste and texture and animal welfare as other reasons for spending more.

The researchers reported: ‘The demand for organic food products is steadily increasing, partly due to the expected health benefits of organic food consumption.

‘On the basis of the study carried out under well-controlled conditions, it cannot be concluded that organically grown onions, carrots, and potatoes generally have higher contents of health-promoting secondary metabolites (polyphenols) in comparison with the conventionally cultivated ones.’